U.S. Pat. No. 6,515,220 B1 (2003) to Carpenter, Jr. discloses a chemically activated grounding electrode constructed from a copper cylinder, a copper upper collar and a copper screw on cap. The copper cylinder has a lug onto which a grounding cable may be exothermically welded. During manufacturing the upper collar is exothermically welded to the cylinder, and the lug is welded to the cylinder.
An osmotic conductor is poured into the cylinder, and then the electrode is buried in the earth with the cap accessible at or above the earth's surface. The threads for the cap are traditional 360° threads. In the field the traditional 360° threads become galvanically corroded. When this happens, the osmotic conductor inside the cylinder cannot be checked or replaced. Copper was found to deteriorate over time, and some applications required zinc or tin coatings on the copper cylinder. When this is done, corrosion from dissimilar metals occurs at joints. The end user could not bolt on a grounding cable of his own choice since the exothermic welded grounding cable was shipped with the grounding electrode.
What is needed is a corrosion resistant construction for the cylinder, a single mold construction for the collar and the attachment lug, a one metal construction to avoid corrosion at joints, a non-corroding cap attachment means, and a multi-purpose lug connector for the grounding wire.
The present invention is made of all stainless steel construction. A multi-purpose connector provides for either an exothermic weld connection and/or a wire through stud connection using a bolt to the grounding wire. The cap has a pair of thick ramp type threads which lock with a 90° turn of the cap. Thus, a longer life grounding electrode is provided that can perform in all soil conditions without a costly coating procedure for the cylinder.